Stabilization of ε-iron carbide as high-temperature catalyst under realistic Fischer–Tropsch synthesis conditions

Abstract

The development of efficient catalysts for Fischer–Tropsch (FT) synthesis, a core reaction in the utilization of non-petroleum carbon resources to supply energy and chemicals, has attracted much recent attention. ε-Iron carbide (ε-Fe2C) was proposed as the most active iron phase for FT synthesis, but this phase is generally unstable under realistic FT reaction conditions (> 523 K). Here, we succeed in stabilizing pure-phase ε-Fe2C nanocrystals by confining them into graphene layers and obtain an iron-time yield of 1258 μmolCO gFe−1s−1 under realistic FT synthesis conditions, one order of magnitude higher than that of the conventional carbon-supported Fe catalyst. The ε-Fe2C@graphene catalyst is stable at least for 400 h under high-temperature conditions. Density functional theory (DFT) calculations reveal the feasible formation of ε-Fe2C by carburization of α-Fe precursor through interfacial interactions of ε-Fe2C@graphene. This work provides a promising strategy to design highly active and stable Fe-based FT catalysts.

Biosugarcane-based carbon support for high-performance iron-based Fischer-Tropsch synthesis

“…36-1249) emerged. The HRTEM image and the corresponding FFT pattern of spent Fe 4 /C bio (Figure S5) also proved that the measured lattice spacings of 0.21 nm corresponded to the (101) planes of ε-Fe 2 C. Recent works (Lyu et al, 2020b;Xu et al, 2014) had shown that ε-Fe 2 C was a more active phase than c-Fe 5 C 2 in FTS and this was another significant reason for the high performance of biosugarcane-based Fe c /C bio catalysts. And the formation of ε-Fe 2 C was not a coincidence.…”

Ambient-pressure hydrogenation of CO2 into long-chain olefins

“…As for the CO-TPD profile of activated CuFeO 2 , two peaks at 290 and 501 °C appeared, corresponding to non-dissociative and dissociative adsorption of CO, respectively (Fig. 4a ) 34 , 37 . The non-dissociative adsorption of CO* was further supported by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements using CO as a probe molecule.…”

“…The CO-TPD profile of activated Fe 2 O 3 shows a peak at 508 °C for dissociative adsorption of CO (Fig. 4a ) 34 . Considering that activated Fe 2 O 3 comprised Fe 3 O 4 and χ-Fe 5 C 2 , we proposed the reaction scheme of activated Fe 2 O 3 as that for Fe-based catalysts previously reported 16 , 35 , 36 .…”

Functionalized Carbon Materials in Syngas Conversion

“…[207] Lyu et al recently succeeded in stabilizing an ε-Fe 2 C phase, which was considered as the most active but not stable phase under typical FT reaction conditions, inside graphene layers by a pyrolysis method. [208] The obtained ε-Fe 2 C@graphene catalyst exhibited an ultrahigh activity (1258 μmol CO g Fe −1 s −1 ) in FT synthesis, and meanwhile, the catalyst exhibited excellent stability in 400 h reaction. In addition to the activity and stability, the product selectivity could be tuned by the confinement effect.…”